What's a Zwickelbier?
Here's a Zwickelbier:
A zwickel is a sampling valve on the side of a beer fermenter or maturation tank. A beer poured from a zwickel on a maturation tank is called a zwickelbier (German spelling). Brewers (sober!), may refer to this as zwickel-teasing.
Zwickelbier usually is not very carbonated, and, because it hasn't been filtered, will contain yeast. Brewers will sometimes rack (transfer) the beer directly into casks and serve it as is. Also referred to as kellerbier, this is obviously as fresh as a beer can be ... when served and consumed immediately!
This photo was taken at the Mad Fox Brewing Company in late June 2010 (and is reproduced here by permission.) The beer is an American Pale Ale, and it's the first beer ever poured at the brewpub, which is scheduled to open in mid July 2010.
In the comments below, two readers pointed out inaccuracies in what I had written, or as Alan put it, a quibble over a zwickel. Their observations were significant enough that I've amended my post.
Real Ale —also known as cask-conditioned ale (or lager) is unfiltered beer that has undergone a final fermentation WITHIN a cask, and then served from that cask, without extraneous gas pressure, either pumped from the cask by hand, or by simply opening a tap which has been hammered into a bung. Think of a cask as a fermenter (albeit a small one) containing active, still fermenting, beer. That's fresh!
Since zwickelbier is beer which is served from the vessel in which it was fermented (in this case a brewery fermenter), it could in a sense be considered real ale (or real lager). If the fermenter is bunged (sealed) at some point near the end of fermentation, the beer will be carbonated. It may be cloudy, from proteins in solution and suspended yeast .
Suffice it to say, however, that simply racking (transferring) unfiltered beer into a cask does not make it cask-conditioned real ale. Some craft breweries in the US have been known to do this.
Not so Bill Madden —Mad Fox's brewmaster— a passionate advocate for cask-conditioned ale. At the Northern Virginia Sumer Brewfest, today and tomorrow, Madden will be pouring his American Pale Ale zwickelbier. At his blog, he very carefully explains that it will not be cask-conditioned ... but that it will be fresh. It will be the first public sampling of Mad Fox beer brewed on-site.
The [kellerbeir] will be gravity served out of firkins [10.8 gallon casks], but this is not proper Real Ale or Cask Ale. There will be no secondary fermentation or finings used. You’ll have to wait until Mad Fox opens and the Real Ale has matured in casks for that experience.
Years ago, at the Oxford Brewing Company (my first professional brewing gig), brewer Dan Carter showed me how to pull samples from the outflow side of the filter. He taught me how to examine the beer for color, consistency, and flavor. The process included measurement and organoleptic analysis. Another way of saying this: we tasted the wonderfully cold, fresh beer. Dan called the sampling port a "happy valve." Indeed!
Photos from the Northern Virginia Summer Brewfest: here.
This post is one in a series on Cask Ale: Fobbing at the Tut.